Let me preface this post with this: I'm not saying "bigfoot" does NOT exist. Stranger things have happened. There is certainly evidence of SOMETHING, but nothing that can rise to the level of certainty.
So, my background on the matter: I had a passing interest in cryptozoology for a couple of decades. Followed things like Bigfoot, Lock Ness, Champ, etc... Probably one of the reasons I studied Biology in college. Took courses in Ecology, Environmental Ecology, Populations, etc... Gave me what I believe is a pretty decent foundation, but by no means am I at the same level as a Ph. D..
So, that said, on the topic of a large bipedal primate, I tend to look at not just the reports, but what it would take to support such a beast. What is their likely habitat? Food sources? Range? How many individuals would it take to support a stable population? When are they most active? For these questions, the best approach is to look at known analogs. If we want to stick to semi-bipedal, that leaves us with Lowland Gorillas, Chimpanzees (too small, really), and Orangutans (more arboreal, but close). Habitats are all dense jungles. All pretty warm, and wet. Lots of food sources, as anything this size needs considerable calories. Fruits and the like are staples, though meat is not unheard of. In the search for food, their ranges are on the order of 2.5 to 5 square miles. Orangutans, being climbers, can travel much farther. Both the gorillas and the chimps stay primarily is family groups. Orangs tend to be more solitary. Research shows populations need to be larger than about 250 individuals to be "healthy". Smaller leads to too little genetic diversity. And finally, all Great Apes are active during the day, and not at night. Most forage in the morning and evening, rest during the heat of the day, and nest at night.
So, I would expect "bigfoot" to fall somewhere into the description above. Similar in most ways, different in a few. For its reported size, it would need on the order of 10,000 calories worth of fruit per day, year around. It seems to be a loner, so a range of healthy adults, at the low end, would need to be 625 square miles, with an adult every 2.5 square miles. On the high end, 1,200 square miles with an adult every 5 miles. And that is for a just barely healthy population of 250 adults.
So, this is why I start getting skeptical, especially in highly populated places like Indiana. There just isn't anywhere for that many large primates to hide. Even the most remote parts of the state have several people per square mile. Sure there are "sightings". But no one seems to have a working camera (they are all blurry, every time). No skeletons. No carcasses. No scat. Some footprints, maybe. Some hair, that can't be fully identified. People keep having "sightings" at night, but it is extremely rare for large primates to be active at night.
BUT.. that's why I pointed our Russia. We KNOW there was a hominid species there, living alongside modern humans, only a few thousand years ago. The area is INCREDIBLY remote. Not much in the way of food for a large primate, but, well, it could still work. Maybe a small population is still holding on?
And I suppose my skepticism could be fueled by the current crop of TV shows. They paint "bigfoot hunters" as a bunch of buffoons. At least the few specials on NatGeo and Science have tried to be scientific. Unfortunately, they are either denied access to any real data, of the data they collects turns out to disprove "bigfoot" (hair that ends up being from a horse, for example).
I'm not saying you shouldn't believe. Heck, my wife LOVES this stuff, and believes it with all her heart. And, winning me over is EASY. Bring me some DNA, a skeleton that can be dated and reconstructed, or the living breathing beast in the flesh.